Carbohydrate-protein interactions have emerged as important recognition systems in the orchestration of mechanisms of innate immunity1. Unlike the usual situation of receptor-ligand pairs2, a picture is emerging of recognition systems that operate as triads: receptors, ligands and carriers. Here the receptors are lectins3, the ligands are oligosaccharides, and when they are optimally assembled on carriers (proteins or lipids) functional counter-receptors are formed, as depicted in Figure 1.